System and a method for indicating information representing battery status of an electronic device

ABSTRACT

The invention relates to a system for indicating information representing battery status of an electronic device. The system comprises a charging unit and an electronic device. The charging unit comprises: charging means; wireless communication means; and indication means. The electronic device comprises a rechargeable battery; charging means; and wireless communication means. During the wireless charging of the electronic device the electronic device is configured to detect information representing the battery status of said electronic device and to communicate the detected information representing the battery status to the charging unit, and the charging unit is configured to receive the information from the electronic device and to indicate at least part of the received information representing the battery status of the electronic device. The invention relates also to a method for indicating information representing battery status of an electronic device.

PRIORITY

This application claims priority of Finnish patent application numberF121085418 which was filed on 7 May 2018, the contents of which areincorporated herein by reference.

TECHNICAL FIELD

The invention concerns in general the technical field of batteryoperated electronic devices. Especially the invention concerns systemscomprising a battery operated electronic device and a charging unit forthe electronic device.

BACKGROUND

Typically, wearable electronic devices, such as smartwatches or smartrings, are using rechargeable battery as an energy source. When thebattery is running low, i.e. its energy is used, it needs to be charged,typically with a charger. The battery may be connected with electricalcontacts to the charger or the charging may be wireless. In the wirelesscharging the charger comprises a transmitting coil to transmitelectromagnetic power to the receiving coil which is integrated orembedded in the chargeable wearable device. The received electromagneticpower may be then be transformed and filtered into electric current tocharge the battery of the wearable device. Many wearable devicescomprise a display or some kind of indicator for indicating the statusof the charging of the wearable device. Simply, the indicator mayindicate that the battery is fully charged or it may indicate alsofractional levels of charged status, such as ¼-½ or ¾ charged. Theindication may also be percentage of charged status, for example 75%.

Some wearable devices are small and have no indicator or display forindicating the charging status.

Some wearable devices may comprise a wireless connection to a mobiledevice and a mobile application running in the mobile device. Thewearable device may communicate the charging information to the mobiledevice and the mobile application may show the charging status asdescribed above. The use of mobile device for indicating the chargingstatus is not user friendly as there is need to keep a mobile deviceavailable and the mobile application running.

According to one prior art solution the charging status may be detectedfrom the charging current in the charger. However, the drawback of thissolution is that in small and very low power devices, the battery andthe receiving coil of the device are small, and thus the correspondingcharging current is also very low. It is very challenging to detect thecharging status from the charging current in the charger, if thecharging current is very low. Hence, this prior art solution is suitableonly for larger devices and batteries having larger charging currents.

SUMMARY

The following presents a simplified summary in order to provide basicunderstanding of some aspects of various invention embodiments. Thesummary is not an extensive overview of the invention. It is neitherintended to identify key or critical elements of the invention nor todelineate the scope of the invention. The following summary merelypresents some concepts of the invention in a simplified form as aprelude to a more detailed description of exemplifying embodiments ofthe invention.

An objective of the invention is to present a system and a method forindicating information representing battery status of an electronicdevice. Another objective of the invention is that the system and themethod for indicating information representing battery status of anelectronic device enable that the battery status of an electronicdevice, which does not have any indicator to indicate its batterystatus, may be indicated during the charging.

The objectives of the invention are reached by a system and a method asdefined by the respective independent claims.

According to a first aspect, a system for indicating informationrepresenting battery status of an electronic device is provided, whereinthe system comprises: a charging unit comprising: charging means forwireless charging; wireless communication means for communication withthe electronic device; and indication means for indicating informationrepresenting the battery status of the electronic device, and theelectronic device without means for indicating information representingthe battery status of said electronic device, the electronic devicecomprising: a rechargeable battery; charging means for wirelesscharging; and wireless communication means for communication with thecharging unit, wherein, during the wireless charging of the electronicdevice: the electronic device is configured to detect informationrepresenting the battery status of said electronic device and tocommunicate the detected information representing the battery status tothe charging unit, and the charging unit is configured to receive theinformation representing the battery status from the electronic deviceand to indicate at least part of the received information representingthe battery status of the electronic device.

The wireless communication means of the electronic device may comprisean infrared, IR, transmitter and the wireless communication means of thecharging unit may comprise IR receiver in order to communicate theinformation representing the battery status from the electronic deviceto the charging unit.

The IR transmitter of the electronic device may be an infrared LED,IRLED, used for optical sensing purposes, when the electronic device isnot charging.

Alternatively, the wireless communication means of the electronic devicemay comprise Bluetooth, BT, radio communication unit or Bluetooth LowEnergy, BTLE, radio communication unit and the wireless communicationmeans of the charging unit may comprise BT receiver or BTLE receiver inorder to communicating the information representing the battery statusfrom the electronic device to the charging unit.

The electronic device may be a wearable electronic device.

The indication means of the charging unit may comprise at least one ofthe following: one or more LED indicators, display.

The information representing the battery status may comprise at leastone of the following: current charging status of the battery, estimationof required charging time for full charge.

Furthermore, the charging unit may further be configured to recognizethe electronic device under wireless charging by one of the following:pairing or information based on the received information representingthe battery status.

According to a second aspect, a method for indicating informationrepresenting battery status of an electronic device is provided, whereinthe method comprises: arranging the electronic device to a chargingunit, wirelessly transmitting power from the charging unit to theelectronic device in order to charge the battery of the electronicdevice, detecting information representing the battery status by theelectronic device, communicating the detected information representingthe battery status from the electronic device to the charging unit, andindicating the at least part of the received information representingthe battery status by means of the indicator of the charging unit.

Various exemplifying and non-limiting embodiments of the invention bothas to constructions and to methods of operation, together withadditional objects and advantages thereof, will be best understood fromthe following description of specific exemplifying and non-limitingembodiments when read in connection with the accompanying drawings.

The verbs “to comprise” and “to include” are used in this document asopen limitations that neither exclude nor require the existence ofunrecited features. The features recited in dependent claims aremutually freely combinable unless otherwise explicitly stated.Furthermore, it is to be understood that the use of “a” or “an”, i.e. asingular form, throughout this document does not exclude a plurality.

BRIEF DESCRIPTION OF FIGURES

The embodiments of the invention are illustrated by way of example, andnot by way of limitation, in the figures of the accompanying drawings.

FIG. 1 illustrates schematically an example of a system according to theinvention.

FIG. 2 illustrates schematically another example of a system accordingto the invention.

FIG. 3 illustrates schematically an example of an electronic deviceaccording to the invention.

FIG. 4 illustrates schematically an example of a charging unit accordingto the invention.

FIG. 5 illustrates schematically an example of a method according to theinvention.

DESCRIPTION OF THE EXEMPLIFYING EMBODIMENTS

FIG. 1 illustrates schematically an example of a system according to theinvention. The system comprises at least one electronic device 102 and acharging unit 104. The at least one electronic device 102 may be awearable electronic device that is capable for monitoring, e.g.activity, sleep, heart rate, and/or recovery of the user. Somenon-limiting examples of the wearable electronic device may be, e.g. asmart ring, a smartwatch, a smart garment, etc. In the exampleillustrated in FIG. 1, the electronic device 102 is a smart ring.

The electronic device 102 may comprise an energy storage 106, e.g. arechargeable battery, a receiving coil 108 for wireless charging, andother electronic device related units 110. The receiving coil 108 may beintegrated to or embedded in the electronic device 102. The other devicerelated units 110 of the electronic device may comprise e.g. amicrocontroller; one or more sensors; and/or wireless communicationmeans, e.g. one or more transmitters and one or more receivers, forwireless communication with other wireless devices, e.g. with thecharging unit 104. The different components of the electronic device 102are discussed more detail later in this application.

The charging unit 104 may comprise a transmitting coil 112 for wirelesscharging, a power unit 114, indication means 116, and other chargerrelated units 118. The other charger related units 118 of the chargingunit 104 may comprise, e.g. a microcontroller and/or wirelesscommunication means, e.g. one or more transmitters, one or morereceivers, for wireless communication with other wireless devices, e.g.with the electronic device 102. The different components of the chargingunit 104 are discussed more detail later in this application.

Charging of the electronic device 102 according to the invention isbased on wireless charging. The wireless charging uses anelectromagnetic field to transfer energy between two devices, such aselectronic device 102 and charging unit 104, through electromagneticinduction. In the wireless charging the transmitting coil 112 of thecharging unit 104 transmits electromagnetic power to the receiving coil108 of the electronic device 102. The received electromagnetic power maybe then be transformed and filtered into electric current to charge thebattery of the electronic device 102. FIG. 2 illustrates an example ofthe system 100 according to the invention, wherein the electronic device102 is arranged to the charging unit 104 in order to charge the batteryof the electronic device 102. The charging unit 104 may comprise areceiving part 120 to which the electronic device 102 may be arranged tohold the electronic device 102 substantially stationary during thecharging of the electronic device 102 as shown in the example systemillustrated in FIGS. 1 and 2. Alternatively, the electronic device 102may be arranged on top of the charger unit 104 having no receiving partfor the electronic device 102.

The electronic device 102 according to the invention does not compriseany indication means to indicate information representing battery statusof the electronic device 102. Thus, the user of the electronic device102 is not able to see from the electronic device 102, e.g. when thecharging is fully done, i.e. when the electronic device 102 may bedisconnected from the charging unit 104.

In order to provide indication about the information representing thebattery status of the electronic device 102 for the user of theelectronic device 102 during the wireless charging process, the system100 according to the invention uses the indication means of the chargingunit 104. To provide the information representing the battery status tothe charging unit 104, the electronic device 102 detects informationrepresenting the battery status of the electronic device 102. Thedetection may be provided by the microcontroller of the electronicdevice 102. The charging status of the battery may be detected by thevoltage of the battery. For example, the microcontroller may monitor thevoltage level by detecting the voltage of the battery by its input.Alternatively or in addition, the charging status may also be detectedby charging current driven to the battery. For example, when thecharging voltage is fixed, for example 4.2 volts, the driving currentmay indicate the charge level of the battery. For example, the chargingcurrent of 100 microamperes may indicate that the battery status is 10%or less, the charging current of 10 microamperes may indicate that thebattery status is 90% or more. The charging status may also be detectedas a combination of the voltage of the battery and the charging current.This is very applicable in the case when the battery is first charged bya constant voltage until the battery reaches 4.2 volts, and after thatthe battery is charged by a constant current. The detection may beprovided continuously or at regular or irregular time intervals, e.g.every 1 minute or every 5 minutes. The electronic device 102communicates, by means of the wireless communication means, the detectedinformation representing the battery status to the charging unit 104.The charging unit 104 receives, by means of the wireless communicationmeans, the information representing the battery status from theelectronic device 102 and indicates, by means of the indication means116, at least part of the received information representing the batterystatus of the electronic device 102. This allows that the user of theelectronic device 102 may be aware of the battery status of theelectronic device during the wireless charging, e.g. when the battery isfully charged and the device 102 may be disconnected from the chargingunit 104.

According to one embodiment of the invention, the wireless communicationbetween the electronic device 102 and the charging unit 104 may beoptical communication. The wireless communication means of theelectronic device 102 may comprise infrared (IR) transmitter and thewireless communication means of the charging unit 104 may comprise IRreceiver in order to communicate the information representing thebattery status from the electronic device 102 to the charging unit 104.The optical communication between the electronic device 102 and thecharging unit 104 may be based on any known optical communicationprotocol, e.g. Universal asynchronous receiver transmitter (UART)protocol or Infrared Data Association (IrDA) protocol.

According to one embodiment of the invention, the IR transmitter of theelectronic device 102 may be an infrared LED, IRLED. Preferably, thesame IRLED may be used for optical sensing purposes of the electronicdevice 102, when the battery of the electronic device 102 is notcharging. The optical sensing purposes of the electronic device 102 maybe, e.g. skin color, optical plethysmography, optical blood analysis oroptical heart rate. Alternatively, the electronic device 102 maycomprise a first IR transmitter, e.g. IRLED, for communicating theinformation representing the battery status to the charging unit 104 anda second IR transmitter, e.g. IRLED, for optical sensing purposes.

The optical communication may be a simple on/off indication to thecharging unit 104. For example, when the battery of the electronicdevice 103 is not full, the IRLED is off and when the battery is fullthe IRLED is set on. The microcontroller of the electronic device may beconfigured to detect the information representing the battery status ofthe electronic device 102. Furthermore, in response to detection of fullcharge of the battery, the microcontroller may be configured to set theIRLED on. Alternatively, in response to detection of not full charge ofthe battery, the microcontroller may be configured to set the IRLED off.

Alternatively, the optical communication may be based on pulsing of theIRLED. A continuous pulsing of the IRLED at one frequency, e.g. 38 kHz,may be used to indicate that the battery is fully charged, and nopulsing or pulsing at another frequency may be used to indicate that thebattery is not fully charged. Alternatively, different pulsingfrequencies may be used to indicate different charging levels of thebattery, for example the charging levels may be percentage values of thecharge of the battery or fractional levels of charging status. Forexample, 10 kHz may indicate that the battery has 10% of its capacitycharged, 20 kHz may indicate that the battery has 40% of its capacitycharged, 30 kHz may indicate that the battery has 70% of its capacitycharged, and 40 kHz may indicate that the battery has 100% of itscapacity charged. The above presented frequencies and percentage valuesof the charging capacity are only non-limiting examples and any otherfrequencies and/or percentage values may be used.

Alternatively or in addition, the information representing the batterystatus of the electronic device 102 may be coded to the pulsed datastream. For example, three 8 bits data sequences may be used for codingthe information representing the battery status to be communicated tothe charging unit 104. The charging unit 104, in turn, may be programmedto receive the coded signal from the electronic device 102, to analyzethe code, and to indicate at least part of the information representingthe battery status related to the received and analyzed code.

According to one embodiment of the invention, the wireless communicationbetween the electronic device 102 and the charging unit 104 may beBluetooth (BT) radio communication. In order to communicate theinformation representing the battery status from the electronic device102 to the charging unit 104, the wireless communication means of theelectronic device 102 may comprise BT radio communication unit orBluetooth Low Energy (BTLE) radio communication unit and the wirelesscommunication means of the charging unit 104 may comprise BT radiocommunication unit or BTLE radio communication unit, respectively. TheBT radio communication between the electronic device 102 and thecharging unit 104 may be based on any known BT or BTLE protocol.

The information representing the battery status may comprise at leastone of the following: current charging status of the battery, estimationof required charging time for full charge. The current charging statusmay be fully charged or not fully charged as described above.Alternatively or in addition, the current charging status may bepercentage value of the charge of the battery or fractional levels ofcharging status as described above.

The estimation of the required charging time for full charge of thebattery may be based on a table or a formula for estimating requiredcharging time. For example, the estimation may be based on the followingsimple formula: if the full charging requires 30 minutes, the 50%charging requires 15 minutes etc. Alternatively, the estimation may bebased on historical charging data gathered from previous charging timesof the electronic device 102. The estimation of the required chargingtime for full charge may be performed by the electronic device 102 or bythe charging unit 104.

The charging unit 104 may further be able to recognize the electronicdevice 102 under wireless charging by one of the following: pairing orinformation based on the received information representing the batterystatus. The pairing may be based on any known pairing process, e.g.Bluetooth pairing process. The pairing process may be triggeredautomatically or manually by a user of the electronic device 102. Therecognition of the electronic device 102 is required at least if theestimation of the required charging time for full charge is performed bythe charging unit 104.

The indication means 116 of the charging unit 104 may comprise at leastone of the following: one or more LED indicators, display, or any otherindicator capable for indicating at least part of the informationrepresenting the battery status of the electronic device 102. Accordingto one example, one LED indicator may be used to indicate whether thebattery of the electronic device 102 is fully charged or not. Forexample, the microcontroller of the charging unit 104 may be configuredto set the LED indicator on in response to receiving from the electronicdevice 102 information representing that the battery is fully chargedand otherwise the LED indicator is set off. Alternatively, themicrocontroller of the charging unit 104 may be arranged to set the LEDindicator to emit, e.g. green color, in response to receiving from theelectronic device 102 information representing that the battery is fullycharged and otherwise the LED indicator may be arranged to emit anothercolor, e.g. red color. Alternatively, different blinking frequencies ofthe LED indicator may be used indicate different charging levels of thebattery, for example the charging levels may be percentage values orfractional levels of the charge of the battery. The blinking frequency,i.e. the frequency of the LED indicator switched on and off, may be setaccording the charging level of the battery. For example, 0.5 Hzblinking frequency may indicate that the battery has equal or less than10% of its capacity charged, 1 Hz blinking frequency may indicate thatthe battery has 50% of its capacity charged, 2 Hz blinking frequency mayindicate that the battery has 80% of its capacity charged, andcontinuous light or more than 20 Hz frequency may indicate that thebattery is fully charged.

According to another example, a plurality of LED indicators may be usedto indicate different charging levels of the battery, for example thecharging levels may be percentage values or fractional levels of chargeof the battery, e.g. ¼-½ or ¾ charged. For example, first LED indicatormay indicate that the battery has 10% of its capacity charged, secondLED indicator may indicate that the battery has 40% of its capacitycharged, third LED indicator may indicate that the battery has 70% ofits capacity charged, and fourth LED indicator may indicate that thebattery has 100% of its capacity charged. Alternatively, the pluralityof LED indicators may be used to indicate the estimated remainingcharging time. For example, first LED indicator may indicate 30 minutescharging time and second LED indicator may indicate 15 minutes chargingtime, etc. The microcontroller of the charging unit 104 may beconfigured to set the LED indicators on/off in response to the receivedinformation representing the battery status from the electronic device102.

The above presented colors of the LED indicator, blinking frequencies ofthe LED indicator, and the number or LED indicators are onlynon-limiting examples and any color, any blinking frequency, and anynumber of LED indicators may be used. Also, the above presentedpercentage values of the charging capacity and charging times are onlynon-limiting examples and any other percentage values and charging timesmay be used.

Similarly, the display or any other indicator may be used to indicatewhether the battery of the electronic device 102 is fully charged ornot, to indicate the percentage values of the charge of the battery, toindicate fractional levels of charged status, and/or to indicateremaining charging time of the battery.

FIG. 3 illustrates schematically an example of the electronic device 102according to the invention. As discussed above, the electronic device102 comprises the battery 106, the receiving coil 108 for wirelesscharging and other electronic device related units 110. The other devicerelated units 110 may comprise a microcontroller 302, one or more IRtransmitters 304 a, 304 b, IR receiver 306, and a wireless radiocommunication unit. The electronic device 102 may comprise one IRtransmitter for wireless communication with the charging unit 104 andfor optical sensing. Alternatively, the electronic device 102 maycomprise separate IR transmitters for wireless communication with thecharging unit 104 and for optical sensing. The wireless radiocommunication unit may comprise separate wireless radio transmitter 308and wireless radio receiver 310 as illustrated in FIG. 3. Alternatively,the wireless radio communication unit may comprise a wireless radiotransceiver. The wireless radio communication unit may be for exampleBluetooth (BT) radio communication unit or Bluetooth Low Energy (BTLE)radio communication unit for BT radio communication with any otherwireless devices, e.g. the charging unit 104. Furthermore, theelectronic device 102 may comprise one or more sensors for differentsensing purposes, e.g. body temperature; activity of a user; opticalsensing for heart rate, oxygen level, or skin color etc. The mentionedelements may be communicatively coupled to each other.

The microcontroller 302 of the electronic device 102 may be configuredat least to control the operations of the electronic device 102described above, i.e. wireless charging, detection the informationrelating to the battery status of the electronic device 102,communication with the charging unit 104 through the communicationmeans, and/or providing optical sensing. Furthermore, themicrocontroller may be configured to control any other operations of theelectronic device 102, e.g. any other sensing functions, communicationwith any other devices or units, e.g. mobile devices, such as mobilephones or tablet computers. Furthermore, the microcontroller 302 maycomprise one or more memories being volatile or non-volatile for storingportions of computer program code and any information or parameters,e.g. information representing the battery status of the electronicdevice, information relating to the previous charging times of theelectronic device 102 or sensing related information. Themicrocontroller 302 may be configured to control storing of received anddelivered information.

FIG. 4 illustrates schematically an example of the charging unit 104according to the invention. As discussed above, the charging unit 104comprises the transmitting coil 112 for wireless charging, the powerunit 114, the indication means 116, and other charger related units 118.The other charger related units 118 may comprise a microcontroller 402,IR transmitter 404, IR receiver 406, wireless radio communication unit.The wireless radio communication unit may comprise separate wirelessradio transmitter 408 and wireless radio receiver 410 as illustrated inFIG. 4. Alternatively, the wireless radio communication unit maycomprise a wireless radio transceiver. The wireless radio communicationunit may be for example Bluetooth (BT) radio communication unit orBluetooth Low Energy (BTLE) radio communication unit for BT radiocommunication with any other wireless devices, e.g. the electronicdevice 102. The mentioned elements may be communicatively coupled toeach other. The charging unit 104 may comprise an interface to anexternal power source 412, e.g. mains (e.g. 230V, 110V or 100V) or lowpower source (12V or 5V), such as Universal Serial Bus (USB) charger;laptop; personal computer; portable power supply, e.g. powerbank; etc.The power unit 114 may comprise a transformer for transforming thevoltage from the mains to the low voltage, e.g. 12V or 5V. Furthermore,the power unit 114 may comprise e.g. charging controller and wirelesscharger driver for wireless charging.

The microcontroller 402 of the charging unit 104 may be configured atleast to control the operations of the charging unit 104 describedabove, i.e. wireless charging, communication with the electronic device102 through the communication means, indication of at least part of theinformation representing the battery status of the electronic device102, and/or recognition of the electronic device 102 under wirelesscharging. Furthermore, the microcontroller 402 may be configured tocontrol any other operations of the charging unit 104, e.g.communication with any other devices or units, e.g. mobile devices, suchas mobile phones or tablet computers. Furthermore, the microcontroller402 may comprise one or more memories being volatile or non-volatile forstoring portions of computer program code and any information orparameters, e.g. information relating to the previous charging times ofthe electronic device 102. The microcontroller 402 may be configured tocontrol storing of received and delivered information.

The invention is described above with respect to the system forindicating information representing battery status of an electronicdevice 102. Next an example of the method according to the invention isdescribed by referring to FIG. 5. FIG. 5 schematically illustrates theinvention as a flow chart. To start the wireless charging process theelectronic device may be arranged 502 to the charging unit. The chargingunit may be on continuously or the charging unit may be switched on whenthe electronic device is arranged to it. The switching on the chargingunit may be provided manually by the user or automatically, i.e. thecharging unit may automatically detect that the electronic device isarranged to it and in response to the detection of the electronic devicethe charging unit starts the wireless charging. As discussed above thecharging unit transmits 504 power to the electronic device to charge thebattery of the electronic device. During the wireless charging theelectronic device detects 506 information representing the batterystatus of said electronic device as discussed above. The detection maybe provided continuously or at regular or irregular time intervals, e.g.every 1 minute or every 5 minutes. The electronic device communicates508 the detected information representing the battery status of theelectronic device to the charging unit as discussed above. Furthermore,the indication means of the charging unit indicates 510 at least part ofthe received information representing the battery status of theelectronic device as discussed above. The indication provided by theindicator of the charging unit allows that the user may be aware of thebattery status of the electronic device during the wireless charging,e.g. when the battery is fully charged.

The specific examples provided in the description given above should notbe construed as limiting the applicability and/or the interpretation ofthe appended claims. Lists and groups of examples provided in thedescription given above are not exhaustive unless otherwise explicitlystated.

The invention claimed is:
 1. A system for indicating informationrepresenting battery status of an electronic device, the systemcomprising: a charging unit comprising: charging means for wirelesscharging; wireless communication means for communication with theelectronic device; and indication means for indicating informationrepresenting the battery status of the electronic device; the electronicdevice without means for indicating information representing the batterystatus of said electronic device, the electronic device comprising: arechargeable battery; charging means for wireless charging; and wirelesscommunication means for communication with the charging unit; wherein,during the wireless charging of the electronic device: the electronicdevice is configured to detect information representing the batterystatus of said electronic device and to communicate the detectedinformation representing the battery status to the charging unit, andthe charging unit is configured to receive the information representingthe battery status from the electronic device and to indicate at leastpart of the received information representing the battery status of theelectronic device, wherein the wireless communication means of theelectronic device comprises an infrared, IR, transmitter and thewireless communication means of the charging unit comprises IR receiverin order to communicate the information representing the battery statusfrom the electronic device to the charging unit, wherein the IRtransmitter of the electronic device is an infrared LED, IRLED, used foroptical sensing purposes, when the electronic device is not charging. 2.The system according to claim 1, wherein the electronic device is awearable electronic device.
 3. The system according to claim 1, whereinthe indication means of the charging unit comprises at least one of thefollowing: one or more LED indicators, display.
 4. The system accordingto claim 1, wherein the information representing the battery statuscomprises at least one of the following: current charging status of thebattery, estimation of required charging time for full charge.
 5. Thesystem according to claim 1, wherein the charging unit is furtherconfigured to recognize the electronic device under wireless charging byone of the following: pairing or information based on the receivedinformation representing the battery status.
 6. A method for indicatinginformation representing battery status of an electronic device, themethod comprising: arranging the electronic device to a charging unit,wirelessly transmitting power from the charging unit to the electronicdevice in order to charge the battery of the electronic device,detecting information representing the battery status by the electronicdevice, communicating the detected information representing the batterystatus from the electronic device to the charging unit, and indicatingthe at least part of the received information representing the batterystatus by means of the indication means of the charging unit, whereinwireless communication means of the electronic device comprises aninfrared, IR, transmitter and wireless communication means of thecharging unit comprises IR receiver in order to communicate theinformation representing the battery status from the electronic deviceto the charging unit, wherein the IR transmitter of the electronicdevice is an infrared LED, IRLED, used for optical sensing purposes,when the electronic device is not charging.